CN201513258U - Hybrid exhaust gas recirculation multi-circuit device for serial two-stage supercharged engine - Google Patents

Abstract

A hybrid exhaust gas recirculation multi-loop device of a series two-stage supercharged engine belongs to the technical field of internal-combustion engines, and comprises an engine, a high-pressure stage supercharger, a low-pressure stage supercharger, a high-pressure stage intake pipe, a high-pressure stage exhaust pipe, a hybrid EGR pipe, an EGR splitter, a high-pressure stage EGR branch pipe, a middle-pressure stage intake pip, a middle-pressure stage exhaust pipe, a middle-pressure stage EGR branch pipe, a low-pressure stage intake pipe, a low-pressure stage exhaust pipe and a low-pressure stage EGR pipe, wherein a control valve is respectively arranged on the high-pressure stage, the middle-pressure stage and the low-pressure stage EGR (branch) pipelines. By selecting or combinational use of all the EGR circuits, the engine can be ensured to obtain enough EGR flow under various working conditions, and by utilizing the higher-pressure stage EGR circuits as far as possible, the wasted work of the supercharger and the damage of the high temperature exhaust to the supercharger are reduced. The utility model has reasonable design and simple structure, and is applicable to the series two-stage supercharged engine with high requirements on EGR.

Description

Hybrid exhaust gas recirculation multi-circuit device for serial two-stage supercharged engine

technical field

The utility model relates to an exhaust gas recirculation (EGR) device of an engine, in particular to a hybrid exhaust gas recirculation multi-circuit device suitable for a serial two-stage supercharged engine, which belongs to the technical field of internal combustion engines.

Background technique

EGR technology is an effective way to reduce NOx emissions from internal combustion engines. As emission regulations become more and more stringent, more EGR flow is required to be introduced from the exhaust end of the internal combustion engine to the intake end, and the operating conditions (such as external characteristics and calibration conditions) that did not require EGR in the past are for Meeting new emissions regulations also requires the introduction of EGR. When used in conjunction with a supercharging system, an EGR system introduces exhaust gas from before the turbine to after the compressor to form a high-pressure stage circuit. However, since the operation of the supercharging system changes with the change of the engine operating point, the pressure in front of the turbine cannot always be kept greater than the pressure behind the compressor, especially when the engine is working at a stage of medium-high speed and heavy load, due to the high energy of the exhaust gas, the compressor The pressure behind the engine is greater than the pressure in front of the turbine. If no additional measures are taken, the exhaust gas cannot flow into the intake pipe through the EGR pipe. Another EGR system arrangement is to direct exhaust gas from the outlet of the turbine to the inlet of the compressor, forming a low-pressure stage circuit. Under this arrangement, the pressure difference required by the EGR flow can be achieved under the full operating conditions of the engine, but the high-temperature exhaust gas flowing through the compressor will waste the compression work of the compressor and bring the risk of damage to the compressor.

Utility model content

In order to overcome the deficiencies of the prior art, the utility model provides a hybrid exhaust gas recirculation multi-circuit device for improving the exhaust gas recirculation capacity of a two-stage supercharged engine. According to the change of engine operating conditions, select the appropriate EGR circuit to work to achieve the EGR flow required by the system. Utilize the higher-pressure EGR circuit as much as possible. When the higher-pressure EGR circuit cannot realize the EGR flow, use the control valve to close it and use the lower-level EGR circuit, so that the engine can get all the benefits under various operating conditions. The required EGR flow and reduce the damage of the exhaust gas to the compressor. The utility model can also realize the combination of EGR circuits at the same time to meet the demand for greater EGR flow.

In order to achieve the above object, the technical scheme adopted by the utility model is: the device includes a low-pressure stage air intake pipe, a low-pressure stage air compressor, a medium-pressure air intake pipe, a high-pressure air compressor, a high-pressure air intake pipe, an intercooler, and an air intake manifold , intake manifold, engine, exhaust manifold, high-pressure stage exhaust pipe, high-pressure stage turbine, medium-pressure stage exhaust pipe, low-pressure stage turbine, low-pressure stage exhaust pipe, bypass pipe, bypass valve, high-pressure stage Connecting shaft, low-pressure connecting shaft, mixing EGR pipe, EGR branch, high-pressure EGR branch pipe, medium-pressure EGR branch pipe, low-pressure EGR pipe, high-pressure EGR control valve, medium-pressure EGR control valve, low-pressure EGR control valve , mixed EGR cooler and low-pressure stage EGR cooler, one end of the low-pressure stage inlet pipe is connected to the inlet of the low-pressure stage compressor, and the other end is connected to the atmosphere, and the medium-pressure stage inlet pipe is connected to the outlet of the low-pressure stage compressor and the high-pressure stage compressor Between the inlets of the compressor, the high-pressure stage intake pipe is connected between the outlet of the high-pressure stage compressor and the inlet of the intercooler, the intake manifold is connected between the outlet of the intercooler and the inlet of the intake manifold, and the intake manifold The outlet of the pipe and the inlet of the exhaust manifold are connected to the engine, the high-pressure stage exhaust pipe is connected between the outlet of the exhaust manifold and the inlet of the high-pressure stage turbine, and the medium-pressure stage exhaust pipe is connected to the high-pressure stage turbine Between the outlet and the inlet of the low-pressure stage turbine, one end of the low-pressure stage exhaust pipe is connected to the outlet of the low-pressure stage turbine, and the other end is connected to the atmosphere. The high-pressure stage compressor is connected to the high-pressure stage turbine shaft through the high-pressure stage connecting shaft. The engine is connected to the low-pressure stage turbine shaft through the low-pressure stage connecting shaft. The bypass pipe is installed between the high-pressure stage exhaust pipe and the medium-pressure stage exhaust pipe. The bypass valve is installed in the bypass pipe. The EGR branch is a three-way, Its three connection ports are respectively connected to the high-pressure exhaust pipe, high-pressure intake pipe, and medium-pressure intake pipe through the mixed EGR pipe, high-pressure EGR branch pipe, and medium-pressure EGR branch pipe. The low-pressure stage EGR pipe is installed on the low-pressure stage exhaust pipe. Between the high-pressure stage EGR control valve and the low-pressure stage intake pipe, the high-pressure stage EGR control valve, the medium-pressure stage EGR control valve, and the low-pressure stage EGR control valve are respectively installed in the high-pressure stage EGR branch pipe, the medium-pressure stage EGR branch pipe, and the low-pressure stage EGR pipe. The mixed EGR cooler is installed on the mixed EGR pipe, and the low-pressure stage EGR cooler is installed on the low-pressure stage EGR pipe and placed between the low-pressure stage EGR control valve and the low-pressure stage exhaust pipe.

Through the closing and opening control of the high, medium and low pressure EGR control valves, the system realizes the separate and combined working modes of the high, medium and low pressure EGR circuits.

The beneficial effects of the utility model:

The utility model has a reasonable design and a simple structure, so that the engine can obtain the required EGR flow rate under various working conditions and can reduce the damage of the exhaust gas to the compressor.

Description of drawings

Fig. 1 is a structural schematic diagram of a hybrid exhaust gas recirculation multi-circuit device of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the specific implementation of the present utility model is further described.

As shown in Figure 1, the utility model includes a low-pressure intake pipe 4, a low-pressure compressor 5, a medium-pressure intake pipe 8, a high-pressure compressor 9, a high-pressure intake pipe 13, an intercooler 14, and an intake manifold 15 , intake manifold 16, engine 17, exhaust manifold 18, high-pressure stage exhaust pipe 19, high-pressure stage turbine 24, medium-pressure stage exhaust pipe 25, low-pressure stage turbine 26, low-pressure stage exhaust pipe 27, bypass Pipe 22, bypass valve 23, high pressure stage connecting shaft 28, low pressure stage connecting shaft 29, mixed EGR pipe 20, high pressure stage EGR branch pipe 11, medium pressure stage EGR branch pipe 6, low pressure stage EGR pipe 2, high pressure stage EGR control valve 12 , medium-pressure stage EGR control valve 7, low-pressure stage EGR control valve 3, mixed EGR cooler 21 and low-pressure stage EGR cooler 1, one end of the low-pressure stage intake pipe 4 is connected with the inlet of the low-pressure stage compressor 5, and the other end is connected to the inlet of the low-pressure stage compressor 5. Atmosphere, the medium-pressure inlet pipe 8 is connected between the outlet of the low-pressure compressor 5 and the inlet of the high-pressure compressor 9, and the high-pressure inlet pipe 13 is connected between the outlet of the high-pressure compressor 9 and the inlet of the intercooler 14 Between, the intake manifold 15 is connected between the outlet of the intercooler 14 and the inlet of the intake manifold 16, the outlet of the intake manifold 16 and the inlet of the exhaust manifold 18 are connected to the engine 17, and the high-pressure stage row The air pipe 19 is connected between the outlet of the exhaust manifold 18 and the inlet of the high-pressure stage turbine 24, the medium-pressure stage exhaust pipe 25 is connected between the outlet of the high-pressure stage turbine 24 and the inlet of the low-pressure stage turbine 26, and the low-pressure stage exhaust pipe 25 is connected between the outlet of the high-pressure stage turbine 24 and the inlet of the low-pressure stage turbine 26 One end of the gas pipe 27 is connected to the outlet of the low-pressure stage turbine 26, and the other end is open to the atmosphere. The high-pressure stage compressor 9 is connected to the high-pressure stage turbine 24 through the high-pressure stage connecting shaft 28, and the low-pressure stage compressor 5 is connected through the low-pressure stage connecting shaft 29. It is axially connected with the low-pressure stage turbine 26, the bypass pipe 22 is installed between the high-pressure stage exhaust pipe 19 and the medium-pressure stage exhaust pipe 25, the bypass valve 23 is installed in the bypass pipe 22, and the EGR splitter 10 is a three-way The three connecting ports are respectively connected to the high-pressure exhaust pipe 19, the high-pressure intake pipe 13, and the medium-pressure intake pipe 8 through the mixing EGR pipe 20, the high-pressure EGR branch pipe 11, and the medium-pressure EGR branch pipe 6. The EGR pipe 2 is installed between the low-pressure stage exhaust pipe 27 and the low-pressure stage intake pipe 4, and the high-pressure stage EGR control valve 12, the medium-pressure stage EGR control valve 7, and the low-pressure stage EGR control valve 3 are respectively installed in the high-pressure stage EGR branch pipe 11, Inside the medium-pressure EGR branch pipe 6 and the low-pressure EGR pipe 2 . The mixed EGR cooler 21 is installed on the mixed EGR pipe 20 , the low-pressure stage EGR cooler 1 is installed on the low-pressure stage EGR pipe 2 and placed between the low-pressure stage EGR control valve 3 and the low-pressure stage exhaust pipe 27 . The mixed EGR pipe 20, the mixed EGR cooler 21, the EGR splitter 10, the high-pressure stage EGR branch pipe 11 and the high-pressure stage EGR control valve 12 constitute the high-pressure stage EGR circuit, and the mixed EGR pipe 20, the mixed EGR cooler 21, the EGR brancher 10, The medium-pressure EGR branch pipe 6 and the medium-pressure EGR control valve 7 form the medium-pressure EGR circuit, and the low-pressure EGR pipe 2, the low-pressure EGR cooler 1 and the low-pressure EGR control valve 3 form the low-pressure EGR circuit. When the engine is running at low speed and low working conditions, and the pressure in the high-pressure stage exhaust pipe 19 is greater than the pressure in the high-pressure stage intake pipe 13, open the high-pressure stage EGR control valve 12, close the medium-pressure stage EGR control valve 7 and the low-pressure stage EGR control valve. 3. The high-pressure stage EGR circuit works, the intake air and a part of the exhaust gas are mixed in the high-pressure stage intake pipe 13, pass through the intercooler 14, and then flow into the engine 17 from the intake manifold 15. Under other working conditions, use the higher-pressure EGR circuit as much as possible according to the pressure difference between the two ends of each EGR circuit. When the higher-pressure EGR circuit cannot achieve EGR flow, close the corresponding control valve and use the lower-level EGR circuit. , or use the combined work of the EGR circuit to achieve a greater EGR flow, so that the engine can obtain the required EGR flow under various operating conditions and reduce the damage of the exhaust to the compressor.

Claims (1)

1. A hybrid exhaust gas recirculation multi-circuit device for a serial two-stage supercharged engine, comprising a low-pressure stage intake pipe (4), a low-pressure stage compressor (5), a medium-pressure stage intake pipe (8), a high-pressure stage compressor Engine (9), high-pressure stage intake pipe (13), intercooler (14), intake manifold (15), intake manifold (16), engine (17), exhaust manifold (18), high-pressure stage Exhaust pipe (19), high-pressure stage turbine (24), medium-pressure stage exhaust pipe (25), low-pressure stage turbine (26), low-pressure stage exhaust pipe (27), bypass pipe (22), bypass valve (23), the high-pressure stage connecting shaft (28) and the low-pressure stage connecting shaft (29), are characterized in that they also include a hybrid EGR pipe (20), an EGR branch (10), a high-pressure stage EGR branch pipe (11), a medium-pressure stage EGR branch pipe (6), low-pressure stage EGR pipe (2), high-pressure stage EGR control valve (12), medium-pressure stage EGR control valve (7), low-pressure stage EGR control valve (3), mixed EGR cooler (21) and In the low-pressure stage EGR cooler (1), one end of the low-pressure stage intake pipe (4) is connected to the inlet of the low-pressure stage compressor (5), and the other end is connected to the atmosphere, and the medium-pressure stage intake pipe (8) is connected to the low-pressure stage compressor Between the outlet of (5) and the inlet of the high-pressure compressor (9), the high-pressure inlet pipe (13) is connected between the outlet of the high-pressure compressor (9) and the inlet of the intercooler (14). The manifold (15) is connected between the outlet of the intercooler (14) and the inlet of the intake manifold (16), and the outlet of the intake manifold (16) and the inlet of the exhaust manifold (18) are connected to the engine (17), the high-pressure stage exhaust pipe (19) is connected between the outlet of the exhaust manifold (18) and the inlet of the high-pressure stage turbine (24), and the medium-pressure stage exhaust pipe (25) is connected between the high-pressure stage turbine Between the outlet of (24) and the inlet of the low-pressure stage turbine (26), one end of the low-pressure stage exhaust pipe (27) is connected with the outlet of the low-pressure stage turbine (26), and the other end leads to the atmosphere, and the high-pressure stage compressor (9 ) is connected to the high-pressure stage turbine (24) shaft through the high-pressure stage connecting shaft (28), the low-pressure stage compressor (5) is connected to the low-pressure stage turbine (26) shaft through the low-pressure stage connecting shaft (29), and the bypass pipe (22) Installed between the high-pressure stage exhaust pipe (19) and the medium-pressure stage exhaust pipe (25), the bypass valve (23) is installed in the bypass pipe (22), the EGR branch (10) is a three-way, Its three connection ports pass through the mixing EGR pipe (20), the high-pressure stage EGR branch pipe (11), the medium-pressure stage EGR pipe (6) and the high-pressure stage exhaust pipe (19), the high-pressure stage intake pipe (13), the medium-pressure stage intake pipe (8), the low-pressure stage EGR pipe (2) is installed between the low-pressure stage exhaust pipe (27) and the low-pressure stage intake pipe (4), the high-pressure stage EGR control valve (12), and the medium-pressure stage EGR control valve The valve (7) and the low-pressure stage EGR control valve (3) are respectively installed in the high-pressure stage EGR branch pipe (11), the medium-pressure stage EGR branch pipe (6), and the low-pressure stage EGR branch pipe (2), and the mixed EGR cooler ( 21) Installed on the mixing EGR pipe (20), the low-pressure stage EGR cooler (1) is installed on the low-pressure stage EGR pipe (2) and placed on the low-pressure stage EGR control valve (3) and the low-pressure stage exhaust pipe (27) between.

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